Tunnel kiln loading and discharging mechanism



` TUNNEL KILN LOADING AND DISCHARGNG MEcHANIsM Filed ot. 2a; 195s E. VAN DER PYL March 11, 1958 4 Sheets-She'et 1` INVENTGR. EDWARD l/A/v dE/e Pn.

Marchll, 1958 E. VAN DER PYL 2,826,314

TUNNEL KILN LOADING AND D XSCHARGING MECHANISM Filed Oct. 28, 1953 4 Sheets-Sheet 2 www A Trae/ver March 11,A 1958" TUNNEL KILN LOADING AND DISCHARGING MECHANISM Filed oon 28, 1953 Rag.v 6

Z4 //3 Zia/09 Y 4 Sheets-Sheet 3 N V EN TOR.

1 EDWARD M4N dee PYL A r Toe/VE Y March ll, 1958 TUNNEL KILN LOADING AND DISCHARG'ING MECHANISM l Filed O01. 28. 1953 /75 START E. VAN DER PYL l 2,826,314

4 Sheets-Sheet 4 CEI ,enses/61.6 Mo 'ro/E A TTOR'NEY in operation.

charging mechanism;

TUNNEL KILN LADNG AND'DISCHARGING MECHANISM t Edward Van der Pyl, Heiden, `Mass`.,lassignor to Norton Company, Worcester, Mass., a corporation of Massau `chusctts Y p .Application ocmw 2s, 195s, serial No. sss,s44

11 Claims. (ci. 2144-23) The invention relates to tunnel kilns and more par- '2,826,314 Patented Mar. 11, v1,9518

ice

2 operative engagement with a batt to push the batt into the kiln; y

` Fig. v is a fragmentary detailed view, 'lon an enlarged scale, through o ne of the driving sprockets for the carrier chains, partly broken away and shown in section to show the ball clutch drive for the sprocket; v

tioularly to a loading and dischargemechanism for feeding fgreen ware,` such as, grinding wheels` into and through a tunnel kiln, and for removing the vitrilied ware or wheels ffrom ythe kiln, thus making the kiln automatic One object of theinvention is to provide a. simple and thoroughly practical tunnel,` kiln for rincreasing the rate of production of vitrified products such gas grinding ,wheels Another object is to provide .5a tunnel kiln with an `automatic loading and dischargemechanismwhereby batts, loaded with green ware' may he fed intermittently to and through the tunnel kiln and discharged therefrom at a controlled rate. Another objectffof theinvention is to provide a mechanism for returning the-batts' of fired ware from' the discharge 4'end of vthekiln to the front of the kiln to facilitate loading and unloading of ware. An other object is to provide a return conveyor for convey-` ing batts of fired ware frorngthe discharge end of the kiln to the front or loading station thereof."l Another object is toy provide an automatically vactuated transfermechd ani-sm for transferring batts of tired ware from the discharge end of the kiln onto the return conveyor. 4`Another object Aof the invention is toprovide an automatically actuated transfer mechanism forl transferring batts of tired ware from the return conveyor onto a feed 'conveyor tofacilitate unloading and loading of ware onto the batts 'before being recirculated through thekiln.v A further object is to provide a ware loading and discharging mechanism which is arranged `sol that the ware to be tired may be loaded and the ware after tiring may be discharged at a single` station at the entering end of the kiln.

Fig. 11 is a fragmentary end elevation showing the kiln entering aperture with a batt and the supporting rails therefor, and

Fig. 12 is fan electrical wiring diagram of the electrical actuating mechanisms and the controls therefor.

Referring first to Figs. l, 2, 3, 4 and 5, the kiln which isgenerally indicated by the numeral 15 ismounted on a plurality of legs 16, 17, 18, 19 and 20. Thekln 15 may be substantially the same as that shown in the U. S. Patent No. 2,519,250 to George N. Jeppson, Edward YVan der Pyl and VWallace L. Howe, dated August 15,

1950, vto which reference may be had for details of disclosure not contained herein. As shown, the kiln 15 has the shape of a parallelpiped which is rectangular in cross section and is slightly inclined. The pitch of this inclination is actually about one foot in twenty-three, which is an angle of approximately 2 28. Preferably it should not be much less than say 2, nor much greater than 8. The purpose of the `downward pitch, in Fig. l

the left hand end of the kiln isthe entrance, is to drive more of the hotV gases Vtoward the entrance end of the kiln; some of the gases go to the annealing zone.

The kiln 15 is provi-ded with a longitudinally extending kiln aperture or chamber 21 within which extends `a pair of spaced parallel rails 22 and 23 which serve as slideways or guides for a plurality of batts 24 to carry Iwares to be tired through the kiln. The rails 22 and 23 throughv the kiln'chamber 21,',the'leading edges of 'the Other objects will be in part obvious or in part pointed out hereinafter. Y

In the accompanying drawings illustrating a tunnel kiln, an automatic loading, feeding and discharging mech-f anism for propelling ware through the kiln,

Fig. 1 is a side elevation of an electric tunnel kiln equipped with the improved loading, `feeding and dis- Fig. 2 is a fragmentary side"elevation,`fon scale, of the wheel loading and feeding mechanism;

Fig. 3V is a fragmentary plan view of thev loading =and feeding mechanism las shown in Fig. 2;

Fig. 4 is a front elevation of the tunnel k-iln showing thelloading mechanism; v

Fig. 5 is a rear elevation of the tunnel kiln showing the discharge mechanism;

Fig. 6 is a fragmentary side elevation of the ware dis charge `mechanism as shown in Fig. 5;

Fig. 7 is `a fragmentary plan view of the Ware discharge mechanism;

Fig. 8 is 'a fragmentary sectional view, on an enlarged scale, through one of the work transfer arms, showing4 the pivotally mounted batt transfer member;

Fig. 9 is a fragmentary plan View, on 'an enlarged A t on ja lower level :after which the batts may be then raised to a starting position where the tired wares may be rebatts are provided with a tongue 30 which is arranged to engage, or mate with a groove 31 formed in the trailing edge of the adjacent batt.

The present invention relates to an improved loading and discharging mechanism which is arranged so that batts may be loaded and unloaded by a single operation 'from a point adjacent to the front of the kiln. The discharge mechanism is arranged to return the batts con-` taining the tired ware to the front of thekiln preferably moved therefrom and green ,wares `to be fired loaded on the battbefore it ,starts the next'passage through the ki1n15.'

The 'loading mechanism preferably comprises a pair of spaced continuous link chains 40 and 41 which form a feed conveyor. The chains 40 and 41, at one end, wrap around a pair of sprockets 42 and 43 respectively which are carried by a shaft 44. The shaft 44 is journallcd in `a pair of 4spaced bearings 45 and 46 which are in turn iixedly mounted on a supporting yframe 47. The other ends of the chains 40 land. 41 wrap around a pair of sprockets 48 and 49` respectively which are iixedly 1 mounted on a-drive shaft 50. The drive shaft 50 is journalled in a pair of spaced bearings 51 and 52 which are also fixedly mounted on the frame 47. A plurality of-pairs of rollers 53 are provided on the frame 47 which 'are arranged to serve as idlers to support the chains 40 and `41 between the sprockets above referred to.

scale, of the pusher chains showing theactuating dogs inV `chains 40 and41scrve` asna 'feed conveyor for conveying batts 24 toward Iand onto carier chains and pusher `chains to be hereinafter described. A suitable driving mechanism is provided for the chains 40 and 41 comprising an electric motor 54` having a motor shaft 55 which carries a sprocket 56. The sprocket 56 is connected by a link chain .57 with a sprocket 58 mounted on one end of .the drive shaft 50. The sprockets 58, 43 land 49 .are-fixedly mounted on the drive shaft 50 so that the motor 54 when started will cause a motion of the feed conveyor chains 40 and 41 respectively. The chains 40 and 41 are arranged to support the batts Z4 as they are moved toward the entrance end of the kiln 15.

The feed conveyor chains 40 and 41 are arranged to advance the batts 24 onto a pair of spaced carrier chains 60 and 61. The carrier chains 60 and 61 at one` end wrap around a pair of sprockets 62 and 63 which are rotatably supported on the shaft 50. The other ends of the carrier chains 60 and 61 wrap around a pair of sprockets 64 and 65 which are 'xedly mounted on a drive shaft 66. The drive shaft 66 is journalled in a pair of spaced bearings 67 and 68 carried bythe frame 47. A suitable driving mechanism is provided for rotating the shaft 66 which preferably comprises a motor `69 mounted on the frame 47. `The motor 69 is provided with a motor shaft 70 having a driving sprocket 71 tixedly mounted thereon.

The driving sprocket 71 is connected by a link chain 72 with a sprocket '73 fixedly mounted on one end of the shaft 66. It will be readily apparent from the foregoing disclosure that the motor 69 serves Ato drive the carrier chains 60 and 61 so as to pick up batts from the feed chains 40 and 41 respectively and move the batt 24 toward the entrance tothe kiln chamber 21.

During operation of the kiln there is a continuous line of batts 24 extending lfrom the entrance end 75 to the discharge end 76 of the kiln 15. A plurality of spaced pairs of idler rollers 77 are provided for supporting the carrier chains 60 and 61 between the pairs of supporting sprockets.

Batts 24 are intermittently fed onto therfeed chains 40 and 41 which in turn move the batts intermittently onto the carrierchains"60 and 61 respectively.

A suitable power operated 'mechanism is provided for intermittently pushing the continuous line of batts through the kiln chamber'21 so that the batts 24 containing the green ware to be red are intermittently advanced throughthe kiln aperture 271 from the entrance end 75 to the dicharge end 76 during which time the wares are tired to vitrify the bonding material to the desired and predetermined extent.

A power operated .pushenmecham'sm is provided for moving a batt 24 into engagement with the end of the train of batts which extends through the kiln 1S to advance thc entire train of batts by a predetermined distance, such as a distance equal to the length of one batt.

The mechanism may comprise a pair-of spaced pusher chains 80and 81 which are supported at one end by a pair of spaced sprockets 82 and 83. The spaced vsprockets 82 and 83 are supported on an idler shaft84 which fis journalled in spaced bearings 85 and86 iixedly mounted on the frame 47. The other ends of the pusher chains 80 `and 81 wrap around a pair of spaced sprockets '87 and 88 carried by the drive ,shaft 66. The pusher chains 80 and 81 are each provided with. aY pusher dog 90. The sprockets 64 and 65, which drive the carrier chains 60 and 61, are each connected by an overrunning clutch 89 with the shaft 66 so that the direction of rotation of the shaft 66, sprockets 87 and 88 may be reversed to return the dogs 90 to initialv positions without moving the carrier chains 60 and V6'1. The motor v69 is preferably a reversible motor which serves to rotate the shaft 66 in opposite directions in a manner to be hereinafter described. `Whenthe leading edge of one of the batts 24 reaches avpoint above the centerline of the drive shaft 50, the batt engages the actuatingroller of a limit switch IiSZ to start the'rnotor'69 to start rotation of the drive asaas 14 shaft 66 thereby starting both of the pairs of chains, the

carrier chains 60-61 and the pusher chains 80-81 with their upper surfaces traveling toward the entrance of the kiln 15. During this movement of the pusher chains Sti-81, the dogs 90 move into the dotted line position 90a (Fig. 10) with the face of the dogs 90 engaging the trailing edge of a batt 24. The continued movement of the pusher chains -81 serves through the dogs to push the new batt 24 into engagement with the train of batts extending through the kiln and to ad- Vance the entire train of batts by a distance equal to the length of one batt. When the new batt reaches this position a projection 91 on the dog 90 engages the actuating roller 92 ('Pig. 10) of a limit switch LS4 which serves to reverse the ,direction of rotation of the motor 69 so that pusher chains 80-81 travel in a counterclock wise direction to return the pusher dogs 90 into the full line position (Fig. 1.0). During this reverse movement of the pusher .chains 801-81, due to the overrunmng clutches 89, vno tmotion is imparted to the carrier chains 611-61. When .the dogs 90 reach .the initial position :as illustrated in full Ylitres in Fig. 10, the dogs 90 engage the actuating roller 93 of a limit switch L83 to stop vthe motor69.

It is desirable to provied suitable means for automatically returning batts after the tiring operation to the entering end tofacilitate operation of the tunnel kiln. As illustrated in the drawings, a pair of spaced return conveyor .chains and 101 are provided for returning batts of tired material from-the rear end of the, kiln to the front. The conveyor chains 10D-.101 wrap around a pair of spaced sprockets 102 and 103 respectively which .aresupported on .a shaft 10.4 (Fig. 3) which is journalled in spaced .bearings 105 and 106 fixedly mountedon theframe 47. Y,Similarlythe other ends of the conveyor chains .100 and 101 wrap around spaced sprockets =108 .and 109 respectively which are .mounted onashaft v110 journalled in'spaced bearings 111 and 112 respectively (Figs. 5 and 7). YA plurality of spaced pairs of idler rollers 113 `are provided on the frame 47 betweenthe sprockets10241'03 and v108--109 to support. the upper run of the chains. A plurality of pairsof spaced idlers V114 'areprovided for supporting the slack or lower portion ofthe lconveyor chains 100 and 161 respectively. These idlersare alsosupported on the frame 47.

VA sui-table v drivingnrechanism is provided for the conveyor chains 100-101 comprising a motor 1715 mounted on .the .frame 47.` The motor 115 is provided with a motortshaft 116 having a sprocket -117 which is connected by a -link -chain 118 ,with a sprocket 119` Vfixedly fmounted on vthe shaft104. I

A batt transfer mechanism -is provided for automatically transferring batts of iiied material from thereturn conveyor chains li'-ljilland placing the batts 24 on the feedeonveyorchains-40 41- This mechanismmay comprise a pair 4of spaced transferuarm's Y12S-126 which are tedly mounted on a rotatable shaft 127. ,The shaft 127 is journalled .in bearing `1,28 and 129. The upper 'e'nds ,of the arms v125v126 Ipivotally support a pair of arms 13,0:ar1d 13.1.on studs `132 and 133 respectively. The arms 130 and 131 aretsubstantially -shaped as illustratedl inFig. 4 and are provided `with ribs 1734 and respectively which are arranged to mate with the grooves 25 and26 formed in the under side of the batts 24.

Thelower end of the transfer arms 12S-*126 are similarly provided with substantially -L-shaped arms -141 respectivelywhieh-are'mounted onl pivot studs 142 and 143 respectively which .are carried bythe transfer arms 12S-126. The arms 140 and. ,141 are provided with ribs 1 44 and,145 respectively which arearranged `to mate with Agrooves 25 .and 26 formedinthe side of Vthebatts 24.

The transfer arms ,125 v.and 126 together Vwith their associatedparts ,above ndescribed arefarranged so that when the transfer arms' '125 and 126 are revolved in a gezaaid engage grooves 25 and 26 on a batt 24 which is supported on the return conveyor chains U-101 and swings the batt upwardly and into supporting engagement with the feed conveyor chains 40-41. A suitable driving mechanism is provided for the transfer mechanism above described comprising a motor 150 which drives through a gear reducer unit 151 to a pinion 152 which meshes with a gear 153 iixedly mounted on the shaft 127. Itwill be readily apparent from the foregoing disclosure that when the motor 150 is set in motion a revolving movement will be imparted through the mechanism Vabove described to rotate the shaft 27 and to revolve the transfer arms 125 and 126. A pair of cams or lugs 154-155 are xedly mounted on the side face ofthe gear 153. Thelugs 154 and 155 are arranged in the path` of an actuating roller 156 of a limit switch LS7 which is operatively connected to stop the motor 150 after the transfer arms 125 and 126 have revolved through 180.

When the batt 24 is swung into operative engagement with the feed conveyor chains 4th-41, theV batt24 engages anactuating roller 157 of a limit switch LS1 which is operatively connected `to start the motor 54 thereby starting movement of the feed carrier chains Adill-41 to advance the batt 2 4 toward the entrance end 75 of the kiln 15. l

A similar batt transfer mechanism is provided at the rear end of the tunnel kiln as shown in Figs. 5, 6 and 7. This transfer mechanism comprises a pair of spaced transfer arms 169 and 161 which are xedly mounted on a rotatable shaft 162 journalled in spaced bearings 163 and 164 on the frame 47. l The upper ends of the transf fer arms V1611-161 are provided with substantially L- shaped arms 165 and 166 respectively which are pivotally supported by a pair of studs 167 and 168 carried by the upper ends of the transfer arms 166 and 161 respectively. The arms 165 and 166 are provided with ribs 169 and 170 respectively which are arranged to engage grooves 25 and 26 formed in the ,under side of the batts 24 to lift the batts `24 from the discharge end of the kiln and to transfer the batts of fired ware onto the return conveyor chains .10Q-'181. l n

Similarly the lower ends of the arms 16d-161 are provided with substantially L-shaped arms 175 and 176 supported by studs 177 and 178 which are carried by the transfer arms 160 and 161 respectively. The arms 175 and 176 are provided with ribs 179 and 180 respectively which are arranged to engage grooves 25 and 26 formed in the under sides of the batts 24.

' A drivingmechanism is provided for Vactuating thev transfer mechanism above described comprising a motor `185 which drives a gear reduction unit 186 having a driven pinion 187 which meshes with a gear 188 flxedly mounted on the shaft 162. Itpwill be readily apparent from the foregoing disclosure that when the motor 185 is started, a rotary motion will be imparted to theshaft 162 to revolve the transfer arms 1641-161 in a clockwise direction (Pig. 6).

" Thejgear 188` is provided with cams or lugs 189 and V190 which are arranged to engage an actuating roller 191 of a limit switch L86 to stop the transfer driving motor 185 after the transfer arms 160-161Yhave been revolved through 180"` to effect a tranfer operation transferring a batt 24 from the supporting rails 22-23 at the ,rear end of the kiln and placing the batt on thereturn conveyor chains 1011-161. At the same time actuation of the limit switch LS6 by either the lug 189 or the lug 190 onrthe gear 88 serves to start the motor 115 thereby starting the return conveyor chains 10th-101 so 5? the trailing edge of the batt 24. Continued movement LS5 which is operativelyconnected to start the transfer driving motor 185.

ReferringY now to Fig. l2, to start the operation of the loading and discharge mechanism, a push button start switch 195 is closed to energize a relay switch CRI so as to complete the circuit through line L2. The energizing of CRI sets up a holding circuit so that the line L2 is connected unless or until a stop switch 96 is actuated to deenergize CRI. Assuming a batt 24 on the return conveyor chains 10G-101 to have moved into engagement with the actuating roller to shift the limit switch LSS into the position illustrated in Fig. l2 which closes a circuit to render an electric timer 197 operative. This electric timer may be any of the well known cornmercial timers such as for example the Microflex timer manufactured by the Signal Electric Company of Moline, Illinois. After a predetermined time interval has elapsed a pair of contactors 198 in the timer are closed to close a circuit through the limit switch L37 so as to energize a relay switch CRZ to start the motor 150 lthereby caus-l ing the loader transfer arms 12S-126 to swing in a clockwise direction. The batt 24 on the return conveyor chains 100-101 is picked up by the arms 1410-141 and swung through 180 ready for the next loading operation. When the time transfer arms 12S-126 start mov ing in a clockwise direction, the batt 24 supported by the arms 130-131 is moved onto the feed conveyor chains 413-41. When the batt 24 is moved onto the chains 40-41, the batt engages the actuating roller 157 of the limit switch LS1 to close a circuit thereby energizing a relay switch CR6 and starting the feed conveyor motor 54. Whenpthe relay CR6 is energized a holding circuit is set up through a normally closed limit switch LS2A. The feed conveyor chains 411-41 start moving the batt 24 toward the right (Fig. 2) toward the entrance end 75 of the tunnel kiln 15. There may be several batts on the feed carrier chains t0-151. y

When the rst batt 24 engages and actuates a normally open limit switch L82, a circuit is closed to energize a relay switch CR7 to start the reversible motor 69 which serves to start movement of the carrier chains -61 and the pusher chains Sil-81 with the upper surface travelling toward the right (Figs. l and 2). When relay switch CR7 is energized a holding circuit is set up through a normally closed limit switch L84. The batt 24 moves of the feed conveyor chains 411-41 and onto the carrier chains eli-61. When the leading edge of the batt 24 engages the actuating roller of the limit switch LS2A, the switch opens and breaks the holding circuit for the relay Y switch CR6 thereby stopping the motor 54 and the feed conveyor chains 411-41. The carrier chains 6ft-61 continue the movement of the batt 24 toward the right until the pusher chains Sil-81 advance the dogs 96 carried by the pusher chains 84)-81 into engagement with of the pusher chains 80-81 moves the batt 24 up into n engagement with the end of the train of batts extending through the entire tunnel kiln 15. As the batt approaches this position, a detent 91 on the dogs 9) engages the Y actuating roller 92 of the limit switch LS4 to open the that the batts'supporting fired wares are advanced toward the relay switch CR'7 so as to reverse the motor 69 thereby withdrawing the dogs into the initial position as shown in Fig. l0. When the dogs reach the full line position as indicated in Fig. 10, the dog 90 engages the actuating roller 93 of a normally closed limit Vswitch LSB to open a circuit thereby stopping the motor 69 and the pusher chains 853-81. During the movement of the dogs 9i), the new batt advances the train .of batts extending through the kiln by a distance equal to the length of one batt. At the other end of the kiln one batt is moved on the rails 22-23 out of the discharge end of the kiln.

The lead edge -of the batt 24 engages the actuating roller 192 0f a normally open limit switch LSS to close asada 14 a circuit thereby energizing a relay switch CRS to start the motor 185 which moves the transfer'arms 160-161 in a clockwise direction to transfer a batt from the position illustrated in Fig. 6 onto the return'conveyr chains 1D0-101. Rotation of the gear 188 during movement of the transfer arms 160-161 causes the lug 189 to ride olf the actuating roller 191 of the limit'switch LSG to shift the limit switch in a counter-clockwise direction to set up a holding circuit to maintain the relay switch CRS energizing at the same time 4the limit switch LS5 shifts, it closes a circuit to energize a relay switch CR4 to close a circuit thereby energizing a relay switch CR3. The deenergizing of CR3 closes a Contact so that when the lug 190 on the gear 188 moves through 180 to engagement, the actuated roller 191 will again shift the limit switch L86 into the position illustrated `in Fig. l2, a circuit will be closed to start the motor 115. When the transfer arms 16d-161 have moved through 180 and the lug 190 engages the actuating roller 191, the limit switch LSG is actuated to deenergize the relay switches CRft and CRS and to stop the motor Y1%5 with the transfer arms 160--161 in a substantially vertical position. At the same time the contactors of the limit switch CRS which were previously' closed complete a circuit to start the motor 115 thereby starting the return conveyor chains G-101 so that the batts 24 move in a direction toward the left (Figs. l and 2). When the first batt 24 on the return conveyor chains 100-101 moves into engagement with the actuating roller of the limit switch LSd to actuate the same, the limit switch breaks the holding circuit for the relay switch CRS thereby deenergizing the same and stops the motor 115 to stop the movement of the return conveyor chains 1GO- 101. At the same time actuation of the limit switch LSS by the batt 24 serves to again energize the electric timer 197 to start the next cycle.

In starting up the kiln, before the cycle may be carried on automatically it is necessary to feed either unloaded batts or batts loaded with dummy ware into the kiln so that there is a continuous line of batts from the entrance end 75 to the discharge end 76' and to also position spaced batts on the return conveyor chains 10Q-101. The kiln may be loaded with batts by manually placing batts either unloaded or loaded with dummies onto the feed conveyor chains 40-41 where they will be intermittently advanced as above described. When a suicient number of batts have been loaded in this manner to form a continuous train of batts through the kiln aperture 21 from the entrance end 75 to the desirable end '76, the automatic cycle of operation may then be started in the manner above described by first closing the start switch 195 after which the batts will be intermittently fed into and through the kiln and after being discharged therefrom will be automatically returned to the front of the machine and transferred onto the feed conveyor chains itl-41 where firing wares may be removed therefrom and green wares to be'fired placed on the batt 24 before it again moves into the tunnel kiln 75. The interval of feeding may be regulated by adjusting the time relay 197 so that the desired number of batts per hour may be fed into the kiln. The loading and discharge mechanism may if desired be stopped at any time by opening the stop switch 1%. it will 'oe readily apparent from theforegoing disclosure that after the green wares to be red are placed on the batt, the batts 24 will be intermittently fed into and through the kiln and after being discharged therefrom will be automatically transferred onto the return conveyor chains 10ftlill to the front end of the kiln at which point they will be automatically transferred onto the feed conveyor chains 40-41 for an unloading and loading operation.

It will thus be seen that there has been provided by this invention a tunnel kiln and automatic loading and discharging apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may 'be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a tunnel kiln having a longitudinally extending kiln chamber, spaced rails therein slidably to support a continuous train of batts of Ware to be fired extending from the entrance to the discharge end of the kiln and a loading and discharge apparatus therefor comprising a conveyor mechanism for feeding batts of ware to be fired, power means to move said conveyor mechanism intermittently and successively to advanceY batts toward the kiln entrance, a movable dog arranged to engage the trailing edge of successive batts on the conveyor mechanism positively to move said batts into engagement with the train of batts and to advance the train by a predetermined distance, power operated reversible means to move said dog, a return conveyor mechanism extending from the discharge to the entrance end of the kiln, power means intermittently to move said conveyor, a power operated rotary batt transfer mechanism automatically to pick-up successive batts from the discharge end of the kiln and to swing said batts onto the return conveyor, means including a Isecond power operated vrotary batt transfer mechanism to pick-up successive batts from the other end of the return conveyor and to swing said batts onto the conveyor mechanism to facilitate unloading and loading batts at a single station at the entrance end of the kiln, and lcontrol mechanism to energize the several power means in sequence intermittently to transfer a batt from the return conveyor onto the conveyor'mechanism, then to advance the batt into the kiln thereby causing another batt to emerge therefrom and then transfer a batt onto the return conveyor.

2. In a tunnel kiln, as claimed in claim l, in combination with the parts and features therein specified of a power means including a motor to actuate said rotary transfer mechanism to load successive batts onto the feed conveyor, lmeans including a'timing mechanism to start said motor intermittently after predetermined time intervals to transfer a batt onto said feed conveyor, and means including a limit switch actuated in timed relation therewith to start the feed conveyor motor so as to feed a batt toward the kiln entrance.

3. In a tunnel kiln as claimed in claim 1, in combination with the parts and features therein specified of a. limit switch actuated by and in timed relation with the movable dog to stop and reverse the driving motor after a new batt has advanced the batt train to a predetermined extent, and a second limit switch actuated by said dog when it reaches an inoperative position to ystop the conveyor fand pusher chain driving motor;

4. yIn a tunnel kiln as claimed in claim 1, in combination with the parts `and features therein specified of a limit switch actuated by a batt as it leaves the discharge end of the kiln to start the discharge rotary transfer mechanism to pick-up said batt and to swing said batt onto the return conveyor, and a second limit switch actuated by and in timed relation with the transfer mechanism to start the return conveyor motor so as to convey a batt toward the other end of the return conveyor.

5. In a tunnel kiln as claimed in claim 1, in combination with the parts and features therein specified of an elect-ric timer to control the starting of the loading transfer mechanism, and a limit switch actuated by a batt as it approaches the end of the return conveyor to energize said timer, said timer serving after a predetermined time interval to energize the transfer driving motor so as to transfer a batt onto the feed conveyor to facilitate unloading and loading.

6. In a tunnel kiln as claimed in claim l, in combination with the parts and features therein specified in which the control mechanism includes an electric timer operatively connected to control actuation of the power operated loading transfer mechanism to control the rate of feed of batts to and through the kiln, and means to adjust the timer mechanism so as to control the rate of feed.

7. In a tunnel kiln having a longitudinally extending kiln chamber, spaced rails therein slidably to support a continuous train of batts of ware to be red extending from the entrance to the discharge end of the kiln, and a loading and discharge apparatus therefor comprising a feed conveyor for feeding batts of ware to be fired, power means to move said conveyor intermittently and successively to advance batts toward the kiln, a carrier conveyor to receive batts from said feed conveyor, reversible power means to move said carrier conveyor to advance successive batt-s to the kiln entrance, a pusher chain arranged to be driven in either direction by said reversible power means, a dog on said chain arranged to engage the trailing edge of -successive batts on the carrier conveyor positively to move the batts into engagement with the train of batts and to advance the -train through a predetermined distance, a return conveyor extending from the discharge to the entrance end of the kiln, power means intermittently to move said conveyor, a power operated rotary transfer mechanism automatically to pick-up successive batts from the discharge end of the kiln and to swing said batts onto the return conveyor, and means including a second power operated rotary batt transfer mechanism to pick-up :successive batts from the other end of the return conveyor and to swing said batts onto the feed conveyor to facilitate unloading and loading batts at the entrance end of the kiln.

8. In a tunnel kiln as claimed in claim 7, in combination with the parts and features therein specified of a limit switch actuated by a batt as it approaches the end of the feed conveyor to start the carrier and pusher chain driving motor to cause the batt to move toward the kiln entrance, and a second limit switch actuated by a batt as it leaves the said conveyor to stop the feed conveyor motor.

9. In a tunnel kiln having a longitudinally extending kiln chamber, spaced rails therein slidably to support a continuous train of batts of ware to be fired extending from the entrance to the discharge end of the kiln, and a loading and discharge apparatus therefor comprising a feed conveyor to feed batts of ware to be fired, power means to move said conveyor intermittently and successively to advance batts toward the kiln entrance, a carrier conveyor to receive batts from said feed conveyor, reversible power means to move said carrier conveyor to advance batts to the kiln entrance, an overunning clutch between said latter power means and the carrier conveyor, a pusher chain located adjacent to said carrier conveyor, said pusher chain being driven in either direction by said reversible power means, a dog fixed-ly mounted on said pusher chain successively to engage the trailing edge of each batt on the carrier conveyor to move the batts into engagement with the train of batts to advance the train by a distance equal to the length of one batt, a return -conveyor below the tunnel kiln extending from the discharge to the entrance end of the kiln, a rotary batt transfer mechanism automatically to pick-up successive batts from the discharge end of the kiln and to swing said batts onto the return conveyor, power means intermittently to move said return conveyor, and means including a second vrotary batt transfer mechanism to pick-up successive batts from the return conveyor and to swing said batts onto the feed conveyor to facilitate unloading and loading ata single station.

10. In a tunnel kiln having a longitudinally extending kiln chamber, spaced rails therein slidably `to support a continuous train of batts of ware to be fired extending from the entrance to the discharge end of the kiln, and a loading and discharge apparatus therefor comprising spaced parallel conveyor chains to feed batts of ware to be red, power means to move said chains intermittently and successively to advance batts toward the kiln entrance, a second pair of spaced parallel carrier chains to receive batts from the said feed conveyor chains, reversible power means to move said carrier chains to `advance batts to the kiln entrance, overrunning clutches between said latter power means and the carrier chains, a pair of spaced parallel pusher chains located between said carrier chains, said pusher chains being driven 'in either direction by said reversible power means, a dog iixedly mounted on each of said pusher chains simultaneously to engage the trailing edge of successive batts on the carrier chains to move the batts into engagement with the train of batts and to advance the train by a predetermined distance, a return conveyor `below the tunnel kiln extending from the discharge to the entrance end thereof, a rotary batt transfer mechanism automatically to pick-up successive batts from the discharge end of the kiln and to swing `said batts onto the return conveyor, power means intermittently to move said return conveyor, and means including a second rotary batt transfer mechanism to pick-up successive batts from the return conveyor and to swing said batts onto the feed conveyor chainsto facilitate loading and unloading at a single station. i

l1. In a tunnel kiln having a longitudinally extending kiln chamber, spaced rails therein slidably to support a continuous train of batts of ware to lbe fired extending from the entrance to the discharge end of the kiln, and a loading and discharge apparatus therefor comprising a -feed conveyor for feeding batts of ware to be fired, power means including a motor to move said conveyor intermittently and successively to advance batts toward the kiln, a carrier conveyor to receive batts from said feed conveyor, power means including a reversible motor to move the carrier conveyor to advance batts to the kiln entrance, a pusher chain arranged to be driven in either direction by said reversible motor, a dog on said chain arranged to engage the trailing edge of successive batts on the carrier conveyor to move the batts into engagement with the train of batts and to advance the train through a predetermined distance, a return conveyor extending from the discharge to the entrance end of the kiln, power means including a motor intermittently to move said conveyor, a rotary batt transfer mechanism including a pair of spaced rotary arms, a batt engaging pick-up member pivotally supported adjacent to the end of each of said arms automatically to pick-up successive batts from the discharge end of the kiln and to swing said batts onto the return conveyor, means including a motor to actuate said transfer mechanism, means including a setcond rotary batt transfer mechanism to pick-up 4successive batts from the other end of the return conveyor and to swing lsaid batts onto the feed couveyor to facilitate unloading and loading batts at a single station at the entrance end of the kiln, and means including a motor to actuate said latter mechanism.

References Cited in the file of this patent UNITED STATES PATENTS i 694,519 Baker Mar. 4, 1902 2,224,895 Brooke Dec. 17, 1940 2,523,025 Jeppson et al Sept. 19, 1950 2,623,626 Ditolla Dec. 30, 1952 

